False-twist rubbing device



Feb. 17, 1970 nous H. mo 3,4

FALsfi-TwIs'r mnasme DEVICE Filed D90. 20, 1967 I NVEN TOR.

BY yiifiwi United States Patent US. Cl. 57--77.42 9 Claims ABSTRACT OF THE DISCLOSURE A device for rubbing of rovings and similar yarns and slivers composed of staple fibres comprising two rubbing discs adapted for rotation and disposed in parallel, adjacent, partially overlapping relation to each other, and a yarn guide dis-posed in line with the common chord of the two rubbing discs at the feed side thereof.

The invention relates to a device for rubbing of rovings and similar yarns and slivers composed of staple fibres, which device comprises two rubbing (11368 of about the same size, which discs are placed parallel and close to each other, are partially overlapping each other and arranged in such a manner that they are capable of rotation, and of a yarn guide situated at the feed side and in line with the common chord of the two rubbing discs.

Such a rubbing device is known as an auxiliary apparatus, which is placed between the back and front rolls of a drafting device in order to improve the mutual adherence of the fibres during the drafting of the roving. Besides, a rubbing device, provided with rubbing discs, is known, which is applied for smoothing and compressing of rovings. In this device, however, the roving is not fed between the discs along the common chord. It has appeared that the application of such device for the processing of roving and the like as a rule yields unsatisfactory results. This ought to be attributed in particular to the tendency of the roving to deviate from the common chord of the two rubbing discs, which causes the course of the roving between the discs to be instable and the processing of the roving to be irregular. Moreover, in spite of the smoothing effect of the channel-shaped guidings applied, sticking-out fibres are wound around the roving causing locations with a greatly increased density to arise, which offer more resistance to the later drafting of the roving and give rise to irregularities in the yarn.

It is the object of the invention to provide a rubbing device of the type mentioned above, in which the objections described are overcome. To this end the device according to the invention is characterized in that the yarn guide is located at a distance of at most 10 mm. from the feeding point of the rubbing discs and at that location creates a twist stop for the roving.

Guiding the roving close to the point where it is to enter between the rubbing discs, results in a quiet and stable passing of the roving, while the twist stop situated at a short distance from the feeding point restricts the false twist produced in the roving by the rubbing discs to a small part of the roving and surprisingly appears to be able to prevent that sticking-out fibres are wound around the roving. The result is that by the measures according to the invention a greater evenness in the processing of the roving is obtained. According to the invention a twist stop is obtained, by composing the yarn 3,495,391 Patented Feb. 17, 1970 guide of two guiding elements that are laterally offset in relation to each other. The guiding elements are partially rounded by the roving, because of their being offset, thus preventing the false twist, effected in the roving through the rubbing discs, from being propagated in the roving beyond the guiding elements.

Another way in which, according to the invention, the yarn guide can create a twist stop is that part of the guiding surface of the yarn guide overlaps one of the rubbing discs partially and at such a short distance that the roving is pressed against the rubbing discs by said surface. The pressing influence the roving undergoes between yarn guide and rubbing discs, prevents the false twist from propagating into the roving that still has to pass the pressing point. Consequently the false twist is restricted to the part of the roving that is between the rubbing discs, thus, as it appeared, resulting in a very evenly processed and faultless roving.

With rubbing devices of the type, the invention relates to, another trouble is that in case of irregularities in the thickness of the roving, the rubbing discs, which in the well-known devices are pressed together by a spring or weight load, exclusively and to an increased rate will condense a thicker roving part when it passes through them, whereas the adjacent roving passes freely and uncondensed between the rubbing discs. This causes the irregularities in the roving to exert an increased adverse influence on the quality of the yarn to be produced.

The invention aims at removing this drawback of the rubbing devices known and to this end the device according to the invention is further characterized in that the rubbing discs are provided with a rough surface on that side with which they face each other and that under the rough surface of at least one of the rubbing discs there is a layer of elastic material.

In a rubbing device of such a type the width of the slit between the discs can adapt itself locally to the differences in thickness of the roving, so that the entire roving section that is between the discs, always keeps in touch with the latter, and a more even yarn is obtained. The invention is elucidated hereafter by means of the embodiment of the rubbing device according to the invention as shown by the drawing.

In the drawing:

FIG. 1 shows a side view,

FIG. 2 shows a cross-section according the line II-'II in FIG. 1.

TZIIG. 3 shows a top view of an embodiment of the yarn gui e.

FIIgIG 4 shows a front view of the guide according to FIG. 5 shows a top view of a diflierent embodiment of the guide, and FI151G. 6 shows a side View of the guide according to The roving 1 e.g. delivered by a drafting device is led through the parallel discs 3 and 4 via yarn guide 2.

Discs 3 and 4 are fixed on shafts 5 and 6 and are driven by the latter and with the same speed in the direction shown by arrows 7 and 8.

A layer 9 of rough material is stuck to disc 3, the latter consisting of metal. Disc 4 is likewise provided with a rough layer 10, whereby under rough layer 10 there is, however, a layer 11 o elastic material.

Discs 3 and 4 are arranged in such a position relative to each other that they exert a certain pressure on roving 1. This pressure is evenly distributed by elastic intermediate layer 11 over that part of the roving section that is between discs 3 and 4.

Those points of both discs 3 and 4 that are in touch with the roving, have an equal and equidirectional velocity component parallel to the roving, this causing them to exert a. transporting influence on the roving. Besides, they possess equal but in opposite directions working velocity components perpendicular to the roving and these components cause the desired rubbing action on the roving when it passes between discs 3 and 4.

An enlarged embodiment of guide 2 is shown in FIGS. 3 and 4. This embodiment comprises a base plate 12, which plate serves to attach the guide to the frame of the rubbing device, a troughed guiding 13 and a hook 114 that is provided away from the axle of guide 13. The deflection of roving 1 around hook 14 and around the edge of guide 13 serves the purpose of a twist stop, through which the false twist effected into roving 1 by the rolling action of discs 3 and 4, is confined to the roving section between yarn guide 2 and discs 3 and 4.

Guide 2 together with hook 14 are placed right in front of discs 3 and 4, in order to reduce as much as possible the roving section in which the false twist is effected.

In a different embodiment that is shown in an enlarged scale in FIGS. 5 and 6 guide 2 consists of a plane metal sheet which is provided with a lip 17 bent in line with edge 16. This yarn guide is fixed to the frame of the rubbing device in such a relation to rubbing discs 3 and 4 that lip 17 is partly situated opposite the active surface of rubbing disc 4.

Roving 1 is fed across the upper surface of sheet 15, rounds edge 16 and passes the backside of lip 17 at the bottom side of sheet 15. This causes the roving to be pressed between disc 4- and lip 17 and prevents the roving from being set in rotation by disc 4 before it has passed lip 17. In this way it is conclusively prevented that freely sticking-out fibres wind themselves around the roving.

What is claimed is:

1. Device for rubbing of rovings and similar yarns and slivers composed of staple fibres, which device comprises two rubbing discs of about the same size, which discs are placed parallel and close to each other so as to engage the entire roving section between the two rubbing discs substantially along the common chord of the discs, and which are partially overlapping each other and arranged in such a manner that they are capable of rotation, and a yarn guide situated at the feed side and in line with the common chord of the two rubbing discs, wherein the guide is located at a distance of at most 10 mm. from the feeding point of the rubbing discs and at that location creates a twist stop for the roving.

2. Device according to claim 1, wherein the guide comprises two guiding elements that are laterally offset in relation to each other.

3. Device according to claim 2, wherein the rubbing discs are provided with a rough surface on that side with which they face each other and that under the rough surface of at least one of the rubbing discs there is a layer of elastic material.

4. Device according to claim 1, wherein the rubbing discs are provided with a rough surface on that side with which they face each other and that under the rough surface of at least one of the rubbing discs there is a layer of elastic material,

5. Device for rubbing of rovings and similar yarns and slivers composed of staple fibres, which device comprises two rubbing discs of about the same size, which discs are placed parallel and close to each other, are partially overlapping each other and arranged in such a manner that they are capable of rotation, and a yarn guide situated at the feed side and in line with the common chord of the two rubbing discs, wherein the guide is located at a distance of at most l0 mm. from the feeding point of the rubbing discs and at that location creates a twist stop for the roving, part of the guiding surface of the guide overlapping one of the rubbing discs partially and at such a short distance that the roving is pressed against said one rubbing disc by said surface. I

6. Device according to claim 5, wherein the guide comprises a plane sheet fixed parallel to the axes of the rubbing discs, which sheet at the end of a substantially straight edge has a lip bent at a right angle and in line with this edge, and wherein the guide is fixed relatively to the rubbing discs in such a position that the said edge lies in line with the common chord of the rubbing discs and the lip overlaps one of the rubbing discs at a short distance.

7. Device according to claim 6, wherein the rubbing discs are provided with a rough surface on that side with which they face each other and that under the rough surface of at least one of the rubbing discs there is a layer of elastic material.

8. Device according to claim 5, wherein the rubbing discs are provided with a rough surface on that side with which they face each other and that under the rough surface of at least one of the rubbing discs there is a layer of elastic material.

9. Device for rubbing of rovings and similar yarns and slivers composed of staple fibres, which device comprises two rubbing discs of about the same size, which discs are placed parallel and close to each other, are partially overlapping each other and arranged in such a manner that they are capable of rotation, and a yarn guide situated at the feed side and in line with the common chord of the two rubbing discs, the guide being located at a distance of at most 10 mm. from the feeding point of the rubbing discs and at that location creating a twist stop for the roving, the guide including two guiding elements that are laterally offset in relation to each other, part of the guiding surface of the guide overlapping one of the rubbing discs partially and at such a short distance that the roving is pressed against said one rubbing disc by said surface.

References Cited UNITED STATES PATENTS JOHN PETRAKES, Primary Examiner s. c X's. 57- 512, 51.5

3/1968 Raschle 5777.4 

